Switched-mode power supplies (SMPS) are a well-known type of power supply, suitable for taking a standard input power supply (e.g. a mains power supply), performing a conversion operation and providing a desired electrical power output. An SMPS comprises a switching regulator to switch the input to a transformer coupled with a storage element, e.g. a capacitor or inductor. The output voltage can be regulated using the switching frequency, and/or the transformer/capacitor/inductor characteristics.
It is known to apply different techniques to SMPS to improve operation, e.g. to apply spread-spectrum modulation in an effort to reduce electro-magnetic interference (EMI) in the SMPS.
One of the problems with SMPS however is that with some transformers, a rise in system temperature may lead to a degradation in the wire insulation of transformer windings, and possibly leading to a short circuit in the transformer as the insulation may melt between adjacent windings. The high current levels produced by such a short circuit can act to damage electrical components in the system.
Another problem is that voltage fluctuations in the SMPS can result in fluctuations in the SMPS output, which may result in damage to any components connected to the SMPS output or incorrect functionality due to incorrect voltage levels.
It is an object of the invention to provide a power supply and a method of controlling such a power supply which prevents damage to components due to variations in voltage and current.